Nesting turtles give clues on oil spill's impact

In this photo taken May 14, 2011, a Kemps ridley sea turtle with a tracking antennae applied to her shell with epoxy sits in the sand depositing eggs at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
— AP

In this photo taken May 14, 2011, a Kemps ridley sea turtle with a tracking antennae applied to her shell with epoxy sits in the sand depositing eggs at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

In this photo taken May 14, 2011, Nicole Zellner, a biological science technician for the national parks service, cautions a beach visitor to watch out for nesting Kemps ridley sea turtles at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the region’s population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)— AP

In this photo taken May 14, 2011, Nicole Zellner, a biological science technician for the national parks service, cautions a beach visitor to watch out for nesting Kemps ridley sea turtles at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the region’s population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

In this photo taken May 14, 2011, a volunteer turtle spotter cruises the beach at Padre Island National Seashore National Park in south Texas looking for Kemps ridley turtle tracks. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the region’s population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)— AP

In this photo taken May 14, 2011, a volunteer turtle spotter cruises the beach at Padre Island National Seashore National Park in south Texas looking for Kemps ridley turtle tracks. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the region’s population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

In this photo taken May 14, 2011, a Kemps ridley sea turtle with a tracking antennae applied to her shell with epoxy heads to open sea after depositing her eggs in the sand at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)— AP

In this photo taken May 14, 2011, a Kemps ridley sea turtle with a tracking antennae applied to her shell with epoxy heads to open sea after depositing her eggs in the sand at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

In this photo taken May 14, 2011, Donna Shaver, chief of the Division of Sea Turtle Science and Recovery at Padre Island National Seashore National Park in south Texas measures a nesting Kemps ridley sea turtle Saturday, May 14, 2011 Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)— AP

In this photo taken May 14, 2011, Donna Shaver, chief of the Division of Sea Turtle Science and Recovery at Padre Island National Seashore National Park in south Texas measures a nesting Kemps ridley sea turtle Saturday, May 14, 2011 Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

In this photo taken May 14, 2011, a temperature gauge is inserted into a styrofoam cooler holding Kemps ridley sea turtle eggs, at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)— AP

In this photo taken May 14, 2011, a temperature gauge is inserted into a styrofoam cooler holding Kemps ridley sea turtle eggs, at Padre Island National Seashore National Park in south Texas. A year after an oil spill in the Gulf of Mexico, scientists and biologists are getting their first real idea of how much damage was done to the regionís population of sea turtles as the females begin heading to coastal shores to nest. The greatest concern has been for the Kemps ridley, the smallest sea turtle and the most endangered. (AP Photo/Pat Sullivan)
/ AP

PADRE ISLAND NATIONAL SEASHORE, Texas 
Nearly hidden by brownish sand, the Kemps ridley sea turtle digging furiously with her back flippers as she carved out a flask-shaped hole to lay her eggs wasn't aware of the excitement she was generating among the scientists, volunteers and beach-goers watching from a distance.

They included Donna Shaver, who has been working for more than two decades to save the endangered reptiles. Each spring, she counts their nests and collects the eggs for safe incubation before releasing the turtles' tiny offspring into the sea. Shaver knows this year that each nest she spots has added significance: the turtle that created it survived the largest offshore oil spill in U.S. history.

While scientists in several states are studying the effects of the oil spill on loggerhead and other sea turtles, the Kemps ridley have been of particular concern. The Deepwater Horizon explosion on April 20, 2010 happened when they typically would have been in the area. Most of the 456 visibly oiled turtles rescued by the U.S. Fish and Wildlife Service last year were Kemps ridleys.

At the peak of nesting season, their numbers looked good. As of May 24, 155 Kemps ridley nests had been spotted on Texas shores - more than in all of last year and more than had been counted by that day in 2009 and 2008. The same is true for some other sea turtle species, although they have just started to nest so it might be too early to have confidence in those numbers.

And because sea turtles don't reach reproductive age for at least a decade, the full effects of the oil spill might not be known for years.

"There is fear that some of the turtles that took the year off from nesting or after the turtles were done nesting during the 2010 year, that they entered the waters where the oil had been present," said Shaver, explaining that the reptiles often forage off the hard-hit Louisiana, Alabama and Mississippi coasts before or after nesting along the Texas Gulf Coast.

"There is concern that perhaps those turtles have been impacted from the oil and could then have problems with their reproduction," she added.

The nesting season has long been used to estimate the size of sea turtle populations, and recovery plans for species are based on numbers tallied when females come ashore to lay their eggs. The goal for the Kemps ridleys is to have 10,000 nesters a season by 2020. At that point, the smallest and most endangered sea turtle, could be upgraded to threatened.

Shaver and her volunteers have patrolled the Texas beaches since 1980, driving SUVs and all-terrain vehicles through heat and humidity to collect turtle eggs in plastic foam boxes and bring them to the National Park Service's lab at Padre Island National Seashore. When hatching begins, Shaver sleeps on a cot in her office, caring for the tiny turtles as though they were her babies, making sure to release them into the sea at exactly the right moment.